Interactions of fungal entomopathogens with synthetic insecticides for the control of Kuschelorhynchusmacadamiae (Coleoptera: Curculionidae)

Abstract

This study investigated the interactions between insecticides (acephate and indoxacarb) and fungal entomopathogens (Beauveria bassiana [Bals.‐Criv.] Vuill. strain B27, Metarhizium anisopliae [Metschn.] Sorokin strain ECS1, and a commercial B. bassiana product, Velifer® Biological Insecticide) for controlling the macadamia seed weevil, Kuschelorhynchus macadamiae Jennings and Oberprieler, in the laboratory and glasshouse. In the laboratory, additive interactions between insecticides at their full field concentrations (776 mg AI/L of acephate and 75 mg AI/L of indoxacarb) and fungal entomopathogens at 107 conidia/ml (ECS1 and B27) or at full field concentration (0.5 ml of Velifer®/L) were seen at 6 days and 12 days post‐application. Under the same experimental conditions, synergistic interactions against K. macadamiae were observed 6 days post‐application when fungal entomopathogens at 2.5 × 106 conidia/ml or at 25% of full field concentration (Velifer®) were co‐applied with insecticides at 25% of their full field concentrations, whilst additive interactions were again observed at 12 days post‐application. In the glasshouse, additive interactions between insecticides (at full field concentrations) and fungal entomopathogens (at 107 conidia/ml, or at full field concentration for Velifer®) were obtained at 6 days and 12 days post‐application. The results from this study suggest that acephate and indoxacarb have both synergistic and additive effects against K. macadamiae when deployed together with fungal entomopathogens, depending on the initial concentrations of mixture components. Combined application of entomopathogens with compatible insecticides promises to provide more effective management of K. macadamiae than individual chemical applications.

Resporulation of Metarhizium anisopliae granules on soil and mortality of Tenebrio molitor: Implications for wireworm management in sweetpotato

“…However, since the results with high mealworm mortalities appeared in sterilised soil, the efficacy of fungal granules can be enhanced by integrating the inoculation of fungal granules with a soil disinfecting method, for example, soil fumigation in very high pest populations, or with existing registered insecticides of sweetpotato, for example, Talstar ® or Regent ® . Metarhizium anisopliae has shown compatibility with various insecticides acting synergistically against insect control, for example, M. anisopliae and spinosad (insecticide derived from actinomycete toxin) giving a synergistic effect for wireworm control (Ericsson, Kabaluk, Goettel, & Myers, 2007), and similarly, the farm registered insecticides for macadamia in Australia such as certain concentrations of Lancer ® (acephate) and Avatar ® (indoxacarb) was synergistic with M. anisopliae against macadamia seed weevil (Kuschelorhynchus macadamiae) under both laboratory and glasshouse conditions (Khun et al, 2020). Thus, future studies could be oriented towards the compatibility study between the registered sweetpotato insecticides and M. anisopliae.…”

“…Ongoing economic losses for sweetpotato growers in Australia from continuous pest pressure highlight the need for an alternative to the current pest-control practices (McCrystal, 2014). The adoption of alternative methods such as biological control using entomopathogenic fungi has been proposed as a promising alternative that could be incorporated into an integrated pest management programme (IPM) (Khun, Ash, Stevens, Huwer, & Wilson, 2020;Skinner, Parker, & Kim, 2014). Entomopathogenic fungi (EPF) are soil-resident microorganisms, which are able to survive saprophytically in the soil and naturally infect soil insects (Stone & Bidochka, 2020;Zimmermann, 2007).…”

Compatibilidade in Vitro Entre Beauveria Bassiana E Tiametoxam

“…Para avaliar a interação in vitro entre os isolados de B. bassiana e o inseticida tiametoxam foi realizada metodologia proposta por Khun et al (2021) e Mejía et al (2022) com modificações onde um Erlenmeyer de 125 mL foram adicionados 4 mL de suspensão na concentração de 2 x 10 7 conídios/mL com 4 mL da solução inseticida na concentração de 200 % da dose de campo recomendada. Dessa forma a concentração final foi de 1 x 10 7 conídios/ml e 100% da dose de campo.…”